This invention relates to the field of voltage regulators and, more particularly, to the capability of varying the maximum output power allowed from an alternator in response to temperature changes.
Many voltage regulator/alternator systems have the output power controlled by a temperature device of some sort, mechanical or electrical, so that as the temperature of the alternator rises to some predetermined value, the output is reduced or cut-off to control the temperature. In general, such reduction or cut-off schemes function by shunting the field coil or adding resistance to the field coil circuit and causing considerable power dissipation with attendant ambient temperature increase. One system utilizes three solenoid-operated switching devices, two of which include temperature sensitive elements for providing a low resistance field coil circuit at low ambient temperatures but switching in more resistance when the temperature rises. No electronic voltage regulator is used with this prior art control circuit but power is wasted in the dropping resistors which, again, raises the ambient temperature near the alternator and further reduces the power-handling capability of the alternator.